let username: string = '韩信'

let age: number = 15

let flag: boolean = true

let pageSize: null = null

let data: undefined = undefined

let arr1: Array<number> = [1, 2, 3]
let arr2: number[] = [4, 5, 6]
let arr3: [string, number, string, object] = ['1', 2, '3', { username }]
let arr4: Array<object> = [{ username, age }, {flag, pageSize}]

let obj1: object = { name: '中国电信', age: 18 }

// 枚举类型
enum gender {
  male = 1,
  female = 2
}

const obj1_sex: gender = gender.male

console.log(obj1_sex); // 1

